Render highway=construction

[Phyks]

Hi,

Here is a first draft of render for highway=construction tag as discussed in #28. I'm only playing on opacity so far, since playing with dash would make it difficult to read and risk inducing confusion with the already dashed items (cycleway, footway, etc).

Some examples below:

https://www.openstreetmap.org/way/667390515#map=19/45.77706/3.07498

https://www.openstreetmap.org/way/854996738#map=17/46.14530/3.42974

Render is not perfect, I identified two issues:

1. Playing with opacity makes the road appear grey-er than it should (due to opacity not being applied to the whole object but layer by layer and hence grey is made of semi-opaque white on top of grey outline).
2. Junctions are not rendered nicely (see roundabout).

This however does seem fine to me for a first render and convey the necessary information about "this is a construction area, you might or not be able to cross".

Best,

[jeisenbe]

I would caution against use of opacity, if possible. Since there are different background colors created by different types of land and buildings, using opacity will cause the colors to mix. When there are two different hues this can have unexpected results and make the map less legible.

If you use grayscale the problem is not as severe, but it can still be harder to understand for map users.

[Phyks]

I would caution against use of opacity, if possible.

Indeed, this is a source of problems.

@jeisenbe do you have any other rendering ideas for such highway=construction to convey the same meaning of "this road does not really exist"?